Three suspects face indictment in connection to their alleged role in a brothel network that spans five California cities, including Fairfield, according to a criminal complaint filed Jan. 15 by the FBI.

The complaint, which was signed by Special Agent Rebekah Bills, alleges that the suspects, identified as Roberto Urbina-Gonzalez, 35; Everardo Ibarra Regaldo, 43; and Corina Dominguez, 25, are responsible for transporting and harboring illegal aliens, as well as "failing to register illegal aliens working in a brothel," and conspiracy.

During the investigation, which began in August 2010, it was determined that a duplex in the 800 block of Fifth Street, Fairfield, was used as a brothel, in addition to locations in Stockton, Sacramento, Yuba City and Chico.

State and federal law enforcement officers began looking into the suspected human trafficking organization in the Central Valley operating a network of brothels using Hispanic females as prostitutes -- the majority of whom were from Mexico, officials reported.

Authorities used a number of confidential sources to infiltrate the brothels, and also utilized a "closed-circuit television camera" to conduct surveillance, according to the criminal complaint.

Law enforcement officers observing the Fairfield location believed it was a brothel operated by the same trafficking organization as a the Stockton ring they had begun investigating several months earlier.

Officers observed a number of men visiting the residence for less than half an hour at a time -- behavior consistent with "johns" visiting a brothel to engage a prostitute, Bills reported. Authorities also obtained surveillance footage showing the transfer of females between brothels, as well as "consensually recorded" phone calls supporting the conclusion, she said.

In August, authorities received a business card -- one of the ring's methods for advertising -- for the Fairfield brothel, the complaint recounted. An officer posing as a "john" called the number and was informed of the brothel's hours of operation, the rate, and was given the brothel's location.

Authorities continued to observe the location over the next several months and on Dec. 26, another officer called the brothel posing as a "john" and asked the unidentified male who answered if he had "any young girls available."

Court documents state that the man replied, "Yes, I have one there ... from Mexico." He later confirmed that the female would cost $40. Later in the conversation, the officer stated that he was in Vacaville and would try to arrive in 30 minutes.

According to authorities, the females were kept in each brothel for a week without leaving and were then driven directly to another brothel or taken to a nearby bus station where they either boarded a Southern California-bound bus or were picked up by another member of the ring and driven to a brothel.

Based on the investigation, officials said, it is believed that "many, if not all, of the females" used by the traffickers were "undocumented aliens who are in the country illegally."